1.Pour about 3 parts potassium nitrate to 2 parts sugar into the skillet (5:3 ratio is also good). Measurements don't need to be exact, but you want more KNO3 than sugar. For example, you can use 1-1/2 cups KNO3 and 1 cup sugar. If you use equal amounts of KNO3 and sugar, your smoke bomb will be harder to light and will burn more slowly. As you approach the 5:3 KNO3:sugar ratio, you get a smoke bomb that burns more quickly.
2.Apply low heat to the pan. Stir the mixture with a spoon using long strokes. If you see the grains of sugar starting to melt along the edges where you are stirring, remove the pan from the heat and reduce the temperature before continuing.
3.Basically you are carmelizing sugar. The mixture will melt and become a caramel or chocolate color. Continue heating/stirring until the ingredients are liquefied. Remove from heat.
4.Pour the liquid onto a piece of foil. You can pour a smaller amount onto a separate piece, to test the batch. You can pour the smoke bomb into any shape, onto an object, or into a mold. The shape and size will affect the burning pattern.
5.If you aren't going to clean your skillet immediately, pour hot water into the pan to dissolve the sugar (or else it will be harder to clean). Clean up any residue you may have spilled out of the pan, unless you want mini-smoke bombs on your stovetop.
8.Allow the smoke bomb to cool, then you can peel it off the foil.
Now that you've made your smoke bomb, it's time to light it...